Means for the release of compressed fluids from containers



Feb 28. 1956 R. w. J. cocKRAM l ET A1. 2,736,459

MEANS FOR TEE RELEASE OE OOMRRESSEO ELUIDS FROM CONTAINERS Filed Feb. 4,1953 2 Sheets-Sheet l BY M WW Feb- 28- 1956 R w. J. cocKRAM ET AL2,736,459

MEANS FOR THE RELEASE OF' COMPRESSED FLUIDS FROM CONTAINERS Filed Feb.4, 1953 2 Sheets-'Sheel'I 2 l/V VEA/70195 A rroey United States Patent O2,736,459. MEANS FOR THE RELEASE OF COMPRESSED FLUIDS FROM CUNTAINERSReginald -W. J. Cockram and vNeil Sullivan,V Brentford,

and Cyril Frank Wilkinson, Winsford, Engiand, assignors to The PyreneCompany Limited, Brentford, England Application February 4, 1953, SerialNo. 3355303 Claims Priority, applicaties Great Britain February 8, 195,212 Claims. (Cjl. 22d-S9) This invention relates .broadly to means forthe release .of compressed fluids -from containers.

.For freeextinguishing and other purposes fluids stored in containersunder high pressures must sometimes be released by remote control. Intire-extinguishing apparatus Ausedgin airplanes, to which the inventionis particularly applicable, it is often desirable to use anextinguishing iluidtundera `very high pressure. Now containers arecommonly sealed by lfrangible Adiaphragms and if these are toresisthighpressures they must be strong. To break them, ltherefore,requires considerable force. In an airplane, however, the discharge iscommonly initiated elec- :trically under remote control, and the amountof energy which can be transmitted is so small that it is unable tobreak a large diaphragm and in particular is unable to .makea fairlylarge hole of the kind required if the extinguishing luid is a liquid,e. g. methyl bromide, which must be rapidly ejected as ajet. What isrequired is an apparatus which can be operated by a small current in averyl short time v(a small fraction of'a second) and which is free fromcorrosion and stable throughout a wide temperature range.

It is an object of this invention to provide improved .Illednsforreleasing a compressed fluidby small electrical `impulses.

Another objectfof the invention is Vto enable a sealing diaphragm to bemelted or burnt with great speed to release e compressed fluid.

,heen ,as distinguished froman explosive charge, which may ruptureadiaphragm but which tends to damage parts of the apparatus other thanthe diaphragm, is unstable at high temperatures and has only a limitedlife in which it can be guaranteed to operate. In addition, any remnantsof the diaphragm tend to obstruct the escape of the extinguishing lluid.The charge used in the invention does not depend upon the evolution ofgas as an explosive charge does, but upon the high temperature attainedupon its ignition. Furthermore the ash or residue resulting from theburning of the diaphragm, being brittle, is easily swept aside by theflow of extinguishing liquid fluid.

The invention will be described in detail in its application to a lireextinguisher with reference to the accompanying drawings in which:

Figure 1 shows the head of the re extinguisher in longitudinal section;

Figure 2 shows the diaphragm and the chemical charge on a larger scale;

Figure 3 is a section on the line III- III in Figure 2; and

2,736,459 garantes rieb. 42s, 195e Figure 4 is an elevation taken fromthe left of Figure l.

The apparatus shown is part of a fire extinguisher containing methylbromide under substantial pressure, e. g. 250 lbs. per square inch. Themethyl bromide is keptin a container 1 and is pressurised inconventional manner through the lower end of the container. At its upperend the container has a neck 2 sealed by a diaphragm 3, the edge ofwhich is bentto form a llange 4. VThis flange 4 is soldered into anannular groove 5. in the end of the neck 2. A Y

The chemical charge 9is ina casing 10 composed `of a ring 11 preferablymade of laminated fabric bonded by a synthetic resin and to whichupperand lower discs 12 and 13 are cemented by a synthetic resin cement.The diaphragm 3 consists of acOpper-baSe alloy and is 0.004 inch thick.The upper disc 12 consists of the samealloy and is 0.008 inch thick. Thelower disc 13 consists of copper and is 0.002 inch thick.

An ignitor assembly 14 is cemented into a hole in the ring 11V andcomprises an insulating block 15 bored at A16 and 17 to receive llexibleelectric wires 18 and 19, the ends of the wires being soldered intohollow connector pins 20 and 2 I.scr,ewed into enlarged parts of thebores 16 and 17. The wirelS projects intothe .charge 9 and constitutes aflexible electrode to which one endof an ignitor wire 26 is connected.The wire 19 is connected to a resistance 2 3 which is cemented in anenlarged part 24 of the bore'17, and this in turn is connected to a wire27 constituting a further flexible electrode connected to the other endof the wire 26. This wire 26 is made of an 80% nickel 20% chromiumalloy, 0.0032inch thick, having a resistance of, say, 4 ohms. VBeingcarried by the two exible wires A18 and 27 it is centrally located inthe charge 9 and yet.is free to move with the bulk of the charge bothduring the filling of the casing 1 0 and under any changes in pressurein the charge, brought about for instance by distortion of the diaphragmSiunder the Vinternal pressure on the wcontainer 1. To prevent anyshort-circuiting, insulating beads 22 and 25 @IC Athreaded Over thewires 18 and 27 respectively. The o uter end bead 27 enters the end ofthe bore part v24, so that powder is 4substantially prevented fromenter-ing this part.

The connector pins 20. and21 are` inserted into a socket connected to anelectric battery, say of .-32 volts.V On closing the circuit a Currentwill flow through the ignitor wire 26 and will lead Vto instantaneousignition of the charge. The presence of the resistance 23 `which lis ofabout the same resistance as the ignitor wire 26, is valuable inpreventing short-circuiting ,after ignition.

VIt will Vbe seen that the casing ltlfand ignitorassembly 14 form aself-,contained unit lwhich isput as `such into the iireeextinguisher.'I his lis `-useful in that it .allows the unit to .be .put in positionor `changed ifrrequired without releasingthe presser-e;in thecontainery1.

The casing 10 is held in close contact with the diaphragm 3 by a headmember 29 which has a threaded skirt 30 screwing over the end of theneck 2, which is threaded externally. An opening 31 is made in the headmember 29 to accommodate that part of the ignitor assembly 14 whichprojects out from the ring 11, and before the head member is screwed onthe neck the casing is introduced into the head member through theinterior of the skirt 30, the pins being passed into and through theopening 31. The head member 29 with the ignitor assembly 14 within it isthen screwed over the neck 2.

When the charge 9 is ignited, great heat is generated very rapidly. Thisheat has little effect on the relatively heavy ring 11 before it meltsor burns away the discs 12 and 13 and the diaphragm 3. It is found inpractice that a clean opening 1 inch in diameter can be made, that is tosay, substantially the whole of the seal formed by the diaphragm 3, isdestroyed, in an extremely short space of time. The discs 12 and 13 arealso burnt away, thus leaving a clear passage for the escape of theextinguishing uid to a lateral discharge outlet 32 to which anyconventional hose connector or the like may be connected. Alternatively,by removing a cap 33 on the head member 29 and closing the outlet 32 thelluid can be projected axially.

The disc 12 which forms the outer wall of the casing 10 should be atleast as resistant to the heat generated as in the diaphragm 3 itself inorder to ensure that the disc is not burnt away with complete escape ofthe reacting charge 9 before the diaphragm itself is melted or burnt.This desired result is obtained by the use of the disc and diaphragmthicknesses given above.

Since the charge should have the property of generating heat without anysubstantial evolution of gas, it may be any of the mixtures of metalpowder and a material containing available oxygen which possesses thisproperty. Preferably it is aluminium powder and barium peroxide, whichshould be in the ratio of 5:2 by Weight to insure total combustion. Insuch a mixture reaction causes aluminium oxide to be formed. The heat offormation of this material is very large. The charge 9 should have highbulk density and be closely confined within the casing 10 in order toprovide the maximum available heat energy in the available space. Toobtain high bulk density the powder may be prepared as a paste with avolatile solvent, which is removed by drying.

In the preferred way of making the powder charge and lling the casing10, 50 gm. of barium peroxide and 20 gm. of ake aluminium are mixed to astiff paste with white spirit. Although the paste is stiff, flow takesplace when a quantity is placed in the casing and shaken by tapping, sothat the casing is uniformly lled. The casing is overlled to allow forslight shrinkage on drying, dried for an hour at 90-l00 C. and then foran hour at 150 C. before levelling the charge and closing the casing bythe disc 12. This method of charging the casing is advantageous becauseno pressure need be applied to the charge. Any such pressure would beliable to damage the ignitor 26.

Many variations and modifications of this apparatus shown are possibleand will be apparent to those skilled in the art. For example, thechemical charge may be put in direct contact with the diaphragm in theevent that it is not desired to incorporate it on a self-containedcasing. Again, the charge need not be homogeneous, but rather theignitor element may be surrounded by a small quantity of powder having alower ignition temperature than the remainder of the charge.

We claim:

l. A container for fluid under pressure comprising a container bodyhaving an outlet, closure means for the outlet, ignition means, andchemical heat producing means in juxtaposition to the closing means andadapted to be ignited by the ignition means, whereby heat is producedopening the closure means for the release of the uid.

2. The container of claim 1 in which the heat producing means is indirect contact with the closure means.

3. The container of claim l in which the heat producing means is inindirect contact with the closure means. 4. The container of claim l inwhich the igniting means includes an electrical resistance embedded inthe heat producing means.

5. The container of claim 1 in which a casing is provided for the heatproducing means, and the closure means is a diaphragm, the casingincluding an inner wall in contact with the diaphragm, and an outer Wallfor the casing, the outer wall at least as resistant to heat as thediaphragm.

6. The container of claim l in which the chemical heat producing meanscomprises a mixture of barium peroxide, and aluminium powder.

7. A container for fluid under pressure comprising a container bodyhaving an outlet, a diaphragm closing the outlet, a casing resting onthe diaphragm, a chemical charge stored in the casing operative uponignition to produce heat, the casing including an outer wall and aninner wall in contact with the diaphragm, the casing wall in contactwith the diaphragm being less resistant to heat than the diaphragm andthe outer casing wall being at least as resistant to heat as thediaphragm, and an electrical resistance embedded in the chemical chargeforming an ignitor for the ignition of the chemical charge.

8. The container of claim 7 in which the casing and the ignitor are aunitary assembly, and a discharge head is provided to retain theassembly in position.

9. The container of claim 8 in which is included an ignitor resistance,and insulated llexible leads for the resistance are included in theignitor assembly.

l0. A unitary assembly for use in melting a sealing diaphragm for acontainer for fluid under pressure, the assembly comprising a casingincluding side walls of one thickness, and discs forming opposed majorfaces for the casing, the discs of lesser thickness than that of theside walls, an exothermic charge in the casing, and an ignitor assemblybuilt into the casing and including an ignitor element embedded in theexothermic charge.

1l. The unitary assembly of claim 10 in which is included a resistanceexternally located with respect to the charge for limiting current flowafter ignition of the charge.

12. The unitary assembly of claim l0 in which is included contact pinsprojecting outwardly from the casing, and ignitor wires connecting thecontact pins to the ignitor element.

References Cited in the file of this patent UNITED STATES PATENTS2,562,110 Mathisen et al July 24, 1951 FOREIGN PATENTS 463,168 CanadaFeb. 14, 1950

